1. Field of the Invention
The present invention relates to a display apparatus, and, more particularly, to a constitution of a spacer provided between a rear plate and a face plate within the display apparatus.
2. Description of the Related Art
As a display apparatus capable of being thinned and lightened, a flat panel electron beam apparatus, i.e., a field-emission display apparatus (FED), using an electron-emitting device has been proposed. In the display apparatus like this, a rear plate which has the electron-emitting device and a face plate which has a light-emitting member for emitting light in response to irradiation of electrons are arranged to be opposite to each other. The peripheral edges of the rear plate and the face plate are respectively sealed through a frame member to form a vacuum container, and the inside of the vacuum container is maintained with vacuum (typically high vacuum or ultra-high vacuum). The face plate includes an anode electrode which is laminated to the light-emitting member and to which potential higher than that of the rear plate is applied. Electrons emitted by the electron-emitting device are attracted by the anode electrode and thus irradiated to predetermined positions on the light-emitting member, whereby a desired image is displayed.
Generally, high potential of several hundreds of volts to several tens of kilovolts is applied to the anode electrode in order to not only irradiate the electrons to the predetermined positions on the light-emitting member but also improve luminance of the display apparatus. Moreover, a gap between the rear plate and the face plate is made small as much as possible so as to reduce the thickness of the display apparatus. For these reasons, a substantially high electric field is ordinarily generated within the display apparatus, whereby there is a problem of causing an electric discharge especially between the anode electrode and another internal structure. To cope with this problem, it has been known a constitution in which the periphery of the anode electrode is surrounded by a potential defining electrode having the potential often defined to the ground potential.
Incidentally, plate support members called spacers are provided within the display apparatus, to prevent deformation and destruction of the rear plate and the face plate due to a difference between an internal pressure and an external pressure of the display apparatus. More specifically, since the spacers support the rear plate and the face plate by means of pressing force based on the difference between the internal pressure and the external pressure of the display apparatus, each of the spacers is provided to be in contact with the anode electrode. For this reason, the potential of the spacer on the side of the anode electrode is high, whereby there is a problem of causing an electric discharge between the face of the spacer on the side of the anode electrode and the potential defining electrode. Here, Japanese Patent Application Laid-Open No. 2006-173093 discloses a technique of separating a spacer and a potential defining electrode (i.e., a guard electrode) from each other by a necessary distance to prevent an electric discharge generated between the spacer and the potential defining electrode. Further, Japanese Patent Application Laid-Open No. 2006-236733 discloses that an interval between internal ends of low resistance films on a spacer connected to guard electrodes mutually opposite to each other as interposing an anode electrode between them is made larger than an interval between internal ends of the anode electrode and the guard electrode.